This invention relates to the production of branched poly(arylene sulfide ketone)s. In another aspect, this invention relates to the production of high molecular weight branched poly(arylene sulfide ketone)s. In a further aspect, this invention relates to fiber reinforced composites and other articles of manufacture prepared from these poly(arylene sulfide ketone)s.
Poly(arylene sulfide ketone)s are useful engineering thermoplastics for film, molding, and composite applications because of their high melting points. One process for producing poly(arylene sulfide ketone)s involves the reaction of a dihaloaromatic ketone such as dichlorobenzophenone with an alkali metal sulfide in the presence of an organic amide and water. The alkali metal sulfide can be added as such or can be prepared from the reaction of an alkali metal bisulfide with an alkali metal hydroxide using approximately an equal molar amount of the alkali metal bisulfide with respect to the alkali metal hydroxide. A continuing problem remains however in that the molecular weight of such poly(arylene sulfide ketone)s is often not high enough to maintain a good balance of physical properties in the final article produced from the polymer. Therefore, methods of producing such poly(arylene sulfide ketone)s to an adequate degree of polymerization are still being sought.
A potential method for producing higher molecular weight poly(arylene sulfide ketone)s is polymerization in the presence of a polyhaloaromatic branching agent. However, due to the relatively high reactivity of the dihaloaromatic ketone, a successful branching agent would be expected to require a similar reactivity. Such branching agents are generally not readily available or are relatively expensive. Now a process has been discovered that unexpectedly produces higher molecular weight branched poly(arylene sulfide ketone)s using polyhaloaromatic branching agents that have much lower reactivities and are readily available or are relatively inexpensive.